Electropneumatic brake



FIRST CAR R. E. MILLER ELEGTROPNEUMATIG BRAKE Filed Oct. 7, 1932 5 Sheets-Sheet l CABOOSE SECOND CAR 2 LOCOMOTIVE APPLICATION LAP RELEASE INVENTOR.

RAYMOND E. MILLER A TTORNEY.

Dec. 17, 1935. R MKLLEFQ 2,624,656

ELECTROPNEUMATIC BRAKE Filed Oct. 7, 1952 s Sheets-Sheet 2 W9 |8I 2 184- 1 3 M5 M4 142- H INVENTOR. RAY MONO E. MILLER A TTORNE Y.

Dec, 17, 1935.

R. E. MHLLER 2 2456 ELECTROPNEUMAT I C BRAKE Filed Oct. '7, 1952 s Shecs-Sheet 3 m '1 as? 24a i I5? 5 250 29? *1 24% a 1 a k I u a INVENTORV RAYMOND EJVHLLEF? ATTORNEY.

Patented Dec. 17, 1935 NITED STATES PATENT OFFICE ELECTROPNEUBEATIC BRAKE Application October 7, 1932, Serial No. 636,647

34 Clailns.

This invention relates to brake equipment and more particularly to electro-pneumatic brake equipment for train service.

in the copending application of Clyde C. Farmer, Serial No. 507,783, assigned to the assignee of this application, an elective-pneumatic brake system is disclosed, wherein the electrically operated brake controlling devices are connected in an open circuit so that no energy is consumed by the devices except when the circuit is closed and the devices are energized for effecting an operation of the brake equipment.

In order to apprise the trainmen of any break or failure in the electrical brake controlling system, a signal system is provided which utilizes the conductors of the electrical brake controlling system, but the circuit through the signal device is normally closed so that should one or more of the conductors of the brake controlling syste. become broken or short circuited, or the source of current'supply fail, or the system otherwise become impaired so that insufficient current is available to initiate an application or release of the brakes, the consequent deenergization of the signal system which accompanies such failure, causes the sounding of an audible or the movement of a visual indicator.

The brake equipment disclosed in the above noted copending application is capable of initiating an application of the brakes, either by refiuid from the brake pipe at the locomotive and thereby reducing the brake pipe pressure for effecting serial operation of the brakes from the front to the rear of the train, or by substantially simultaneously energizing the control magnet on each car for effecting local venting of the brake pipe simultaneously at each thereby insuring simultaneous applicaof the brakes on each car.

latter means of effecting an application of t brakes is more desirable than the former,

as in the former case the brakes are ap- T"1-cd first on the cars at the head end of the tl n, and in the case of a long train, the cars head end of the train may be materially ded before the brakes are applied on the cars, and. the slack may run in with conble harshness, whereas in the latter case, brakes are applied in unison on all cars of train and there is but little tendency for owever, in the event of failure of the elecrieal control system, the train may be brought to rest under the influence of the pneumatic contro system. Repairs may then be made to the electrical control system or the train may proceed to its destination :under the control of the pneumatic control system.

It is an object .of this invention to provide an electro-pneumatic train brake and train signal 5 system, such as disclosed 'in the above copending application, with an improved signal device that is responsive to variations in current conditions in the electrical control system, which in addition to giving an audible or visual signal when a failure in the electrical brake control system occurs, will initiate an application of the brakes by simultaneously releasing fluid under pressure from the brake pipe at a point on the locomotive and on the caboose or rear car of the train, thereby causing the train to be brought to rest through an application of the brakes initiated simultaneously at the front and rear cars of the train, and thus preventing the gathering of slack with such force as would occasion severe shock.

A further object of the invention is to provide an electro-pneumatic brake control system having the above noted characteristics, wherein equipment may be provided for automatically causing, in the event .of .a failure such as referred to above, either a service application of the brakes or an emergency application thereof, depending upon the character of the equipment employed.

A further object of the invention is to provide an electro-pneumatic brake control system having a signal device adapted to be operated when a control circuit of the system is interrupted or deenergized either by failure of the conductors of the brake control system,- for giving warning of the failure, or by an operator, for signalling a trainman on the locomotive or caboose, with a brake controlling device adapted to be operated when the circuit through the signal is interrupted continuously for a greater time than that required for operating the signal, as by an accidental break or short circuit in the conductors of the brake controlling system.

These and other objects of the invention that will be made apparent throughout the further description thereof, are attained by means of the brake equipment hereinafter described and illustrated in the accompanying drawings; wherein Fig. 1 is a diagrammatic view of an electropneumatic train brake equipment embodying features of the invention;

Fig. 2 is a sectional view, partially in elevation, of a comb n d signal and brake controlling valve device of the locomotive equipment shown in Fig. 1;

Fig. 3 is a sectional view, partially in section, of a combined signal and brake controlling valve device of the caboose equipment shown in Fig. l; and

Figs. 4 and 5 are views similar to Figs. 2 and 3 respectively, of modified forms of combined signal and brake controlling valve devices of equipment for the locomotive and caboose respectively.

Referring to the drawings, and particularly to Fig. 1., an electro-pneumatic train brake equipment is shown that is similar in many respects to that disclosed in the above mentioned copending application, with the exception of the improved combined signal and brake controlling valve devices and a modified form of enginemans brake valve that is particularly adapted for use with the present improved signal and brake controlling equipment.

The improved equipment shown in Fig. 1 comprises a brake pipe H, an application conductor l2, a return conductor l3 and a release conductor l4, all of which extend throughout the length of the train from the locomotive to the caboose. The equipment carried upon the locomotive comprises an enginemans brake valve device l5, an enginemans brake switch device It, a signal switch device IT, a starting switch i8, a combined electro-magnetic signal and brake controlling valve device 19, an equalizing reservoir 2|, a main reservoir 22, a reduction limiting reservoir 23, a feed valve device 24,

a direct current generator 25, a direct current motor 26, an alternating current generator 21, a tuned impedance coil 28, a transformer 29, and a slow acting relay switch device 3| for controlling the circuit through the primary winding of the transformer 29.

The equipment carried on each car of the train comprises the equivalent of that disclosed in the said copending application, namely a brake cylinder 32, an auxiliary reservoir 33, a triple valve device 34, that is operative upon variations in brake pipe pressure for effecting application or release of the brakes, an electro-magnet valve device 35 that is operative upon energization or deenergization of the electro-magnets thereof for effecting application or release of the brakes, a signal switch device 36, and a tuned impedance device 31 shunting the signal switch 36 for permitting the flow of direct current through the application conductor l2 although the signal switch device may be open.

The equipment carried upon the caboose or last car of the train comprises a brake cylinder an auxiliary reservoir 33, a triple valve device 34 and an electro-magnet valve device 35, all similar to those carried upon the cars of the train, a combined signal and brake controlling valve device 38, a transformer 39, a slow acting relay switch device 4| for controlling a circuit through one of two secondary windings of the transformer 39 and a signal switch 42.

The electro-magnet valve devices 35 are each provided with an application magnet valve device 43 that is connected across the application conductor 12 and the return conductor [3, and a release electro-magnet valve device 44 that is connected across the release conductor l4 and the return conductor l3.

When theapplication conductor I2 and the release conductor M are energized by moving the brake switch member 45 to application position for connecting said conductors to the generator 25, magnet valve devices 44 and :23 are energized and cause an application of the brakes by respectively closing communication from the brake cylinder 32 to the atmosphere and opening communication from the auxiliary reservoir 33 to the brake cylinder.

If it is desired to limit the degree of brake application, the switch 45 is moved to lap position when the desired brake cylinder pressure is attained, wherein the application conductor [2 is disconnected from the generator, thus deenergizing the electro-magnet valve devices and closing communication from the auxiliary reservoir to the brake cylinder. Fluid cannot then flow to the brake cylinder and the brakes remain applied with the desired force.

In order to release the brakes, the brake switch 45 is turned to release position. With the brake switch device 35 in release position both conductors i2 and I4 are disconnected from the generator 25 and the electro-magnet valve devices 43 and 44 are deenergizcd, thus causing the communication from the brake cylinder to the atmosphere to be opened and the communication from the auxiliary reservoir to the brake cylinder to be closed, so that the brakes are released.

From the foregoing, it is apparent that the electro-magnet valve devices are connected in a normally open circuit supplied with current from a direct current generator, and since the circuit is normally open, a break or short circuit any of the conductors l2, l3 and I4, would not ordinarily be made apparent until the brake switch member is moved to either application or lap position when attempting to make an application of the brakes. The discovery of the failure in the electrical brake controlling system at such time might be too late to avert an acci t.

It is, therefore, desirable to apprise the trad-- men of the occurrence of a failure of the circuit or source of supply at the time it occurs, so that the train may be brought to rest through the medium of the pneumatically operated h' controlling equipment in the usual well known manner.

In the brake equipment disclosed in copending application, a warning signal system is provided for immediately indicating, through the medium of current responsive signal devices lo-- cated upon the locomotive and caboose, when the current supply for the electrical brake controlling system fails or when a conductor of the system is broken or short circuited in such man ner as to prevent proper operation of the electrical brake controlling equipment. Means are also provided by means of which a trainman on the locomotive, caboose, or any car of the may cause the signal on the locomotive and caboose to operate at will for transmitting messages.

The improved signal system, like that disclosed in said copending application, utilizes the conductors l2, E3 and 54 upon which alternating current is imposed. The locomotive and all cars of the train and the caboose are provided with normally closed signal switches ll, and respectively. The signal switch ll on locomotive is connected across the application ductor l2 and the return conductor l3 and series with the secondary winding 5i of the transformer 29 on the locomotive, and the sit switch 42 on the caboose is connected across release conductor M and the return conductor l3 i s e w h a condary winding 52 of th transformer 39 on the caboose.

The signal switches 36 on the cars are connected in series in the application conductor 12, and each switch 36 is shunted by a tuned impedance device 37 consisting of a coil 53 and a parallel connected condenser 54, the impedance devices being adapted to pennit direct e-rrent to flow therethrough at all times, but preyenting the passage of alternating current therethrough, Consequently, when a signal switch 35 is opened for the purpose of signalling, the alternating current signal circuit is interrupted. The corn struction of the signal switches ll, 36 and 42 is fully disclosed in said copending application and it need only be pointed out here that they are of such character that when the manual operating lever 30 thereof is operated, the circuit in which the signal switch is included is opened and held open for a predetermined limited time, for example, not exceeding two seconds, regardless of the position of the operating handle, so that the operator cannot, after initiating a sig nailing operation, interfere with the timed circuit closing operation of the signal switch. The purpose of this provision will hereinafter appear.

The normally closed signal circuits, to be hereinafter described, are adapted to be energized by alternating current supplied from the generator 2? through the medium of the transformer 29, the primary coil 58 of which is-connested in circuit with the generator 21,, and a slow acting relay switch 31 which is adapted to be maintained closed when the magnet winding 55 thereof is energized.

Until the signal circuit, including the magnet winding 55, is energized, the switch 3| is held in open position by a spring .55 and consequently the normally open starting switch device It is provided, by means of which the circuit through the primary winding 55 of the transformer '29 may be momentarily closed. Closure of the switch i8 closes the circuit through the primary winding 50 of the transformer .29 and causes energization .of the secondary winding which energizes the signal circuit through the application conductor 52, primary winding .5! of the transformer 39 and return conductor [3.

The primary winding 5! of the transformer on the caboose energizes the secondary windings and 52 of the transformer and conse quently energizes winding 59 of the slow acting relay switch 4! that is connected in the circuit through the winding 58 and causes it to close the relay switch 4! so as ,to establish a second signal circuit energized by the secondary winding 52 of the transformer 39 and which includes the signal switch 42, closed relay switch Al release conductor [4, winding 55 of the relay switch 3! on the locomotive and return conductor [3.

Since the electro-magnet 49 of the improved combined electroemagnet signal and brake controllin valve device 15 on the locomotive is ,connected across the conductors l3 and It}, included in the circuit through the secondary winding 52, it is energized so long as the switch 41- on the caboose remains closed. Energization of the secondary winding 58 also energizes a circuit. through the electro-magnet 59 of the improved combined electro-magnet signal and brake controlling valve device 38 on the caboose, which will hereinafter be more fully described.

When the winding 55 is energized as above indicated, the relay switch 3| is closed and the tained closed. After the relay switch 3| is 5;

closed, the starting switch 58 may be released and permitted to return to its normally open position.

It will be here understood, that the relay switches 31 and 4| are provided with dash pct devices iii and are of such character that they hold the circuits including them closed for more than two seconds after the circuits in their respective magnet windings 55 and 5 9 are open. Con eq en ly, th p n n f su cu by means of the Signal switches cannot cause open ing of the relay switches '31 and 4], since, as previously described, the signal switches are incapable of holding the signal circuits open continuously for more than two seconds.

It is apparent from the foregoing that the electro-magnet ll! on the locomotive is energized through the secondary winding 52 of the transformer $39 on the caboose and the conductors 1 and 14. Therefore, any interruption of the circuit caused by a break in such circuit including conductors l3 and I 4 and enduring for more than 2 seconds, will cause deenergization of the electro-magnet Ml, which will result in the sounding of a signal on the locomotive, and in the case of the present invention an application of the brakes, as will hereinafter appear.

Momentary opening of the signal switch 42 on the caboose for the purposeof signalling, interrupts the circuit through the secondary winding 52 and the electronnagnet on the locomotive and causes a signal on the locomotive to sound, but does not initiate an application of brakes, as will hereinafter appear.

The electro-magnet 5% of the combined, electroemagnet signal and brake controlling valve device 38 on the caboose is connected in a circuit, including a secondary winding 58, and is energized thereby. The winding 158 is energized by the primary winding 5'! of the transformer 39 on the caboose which is connected in a circuit including the conductors l2 and 1.3 and the secondary winding 5! of the transformer v29 on the locomotive, which winding 5! is energized by the primary winding Any break in the 59 circuit through the energizing winding 5| and conductors l2 and i3 enduring for more than two seconds, will cause the signal on the caboose to sound and an application of the brakes, in a manner to be hereinafter described.

Momentary opening of the signal switch l! on the locomotive opens the circuit through the secondary winding 5! and consequently causes deenergization of the electr c-magnet 59 on the caboose and the consequent sounding of the 60 signal on the caboose, but does not cause an application of the brakes because the circuit cannot be held open continuously by the signal switch for more than two seconds.

The deenergization of the secondary Winding 51, by the interruption of the circuit including it for more than two seconds or for sufiicient time to permit opening of the circuit through the magnet Winding 59 of the relay switch M on the caboose, will cause the switch 4| to open and interrupt the circuit through conductors 13K and I l and the winding 55 of the switch 3! on the c mo iv The switch .3! will then intere rupt the circuit through the primary winding 50 of the transformer 29, thereby concurrently deenergizing the circuit through electro-magnets 40 and 60 on the locomotive and caboose respectively, thus concurrently sounding a warning signal thereon and applying the brakes in a manner to be hereinafter described.

Momentary opening of any of the signal switches 38 on the cars of the train interrupts the conductor 52 and causes the simultaneous sounding of the signals on the locomotive and caboose by interrupting the circuit through the primary winding 51 of the transformer 39 on the caboose. This action deenergizes the secondary winding c of the transformer 39 on the caboose and deenergizes the magnet 60 on the caboose. Deenergization of the primary winding 51 of the transformer 39 on the caboose also deenergizes secondary winding 52 and consequently the circuit through conductors I3 and I4 energized thereby and including the electro-magnet winding 40 on the locomotive.

boose is momentarily opened a signal is sounded on the locomotive, and when a signal switch 36 on a car of the train is momentarily opened a signal is sounded on both the caboose and locomotive.

It is also apparent that if the source of current fails or any of the electrical brake controlling conductors I2, I3 and I4 are broken so as to prevent energization of the electro-magnets 43 and 44 of the electro-magnet brake controlling valve devices 35 when energization is desired, for a time exceeding two seconds, signals will sound on both the locomotive and the caboose and that by reason of the improved combined electro-magnet signal and brake control ling valve devices, to be more fully hereinafter described, an application of the brakes of the train is initiated simultaneously at the front end and rear end of the train.

It will be noted that the primary winding 51 and the secondary winding 52 of the transformer 39 are connected in series across conductors I2 and I4 and in the event of the failure of the conductors I3, the windings are energized by the secondary winding 5| of the transformer 29 on the locomotive through the magnet winding 55, conductors I2 and I4 and switch 4I. However, no current is induced in the secondary winding 523 of the transformer 39 on the caboose, due

to the fact that the magnetic flux of the windings 51 and 52 is neutralized as a result of the winding being oppositely wound with an equal number of turns. Consequently, deenergization of the electro-magnet 60 occurs immediately and causes the signal on the caboose to sound. 1 11611 the conductor I3 is broken, the circuit through the electro-magnet 40 is also interrupted, thus causing the warning signal on the locomotive to sound.

The improvements in the brake controlling equipment described above, reside principally in the combined electro-magnet signal and brake controlling valve device used in conjunction with an enginemans brake valve, particularly adapted for use with said brake controlling valve device.

Referring to Fig. 2, the enginemans brake valve device comprises an upper casing section Z i, a lower casing section 12 and an intermediate casing section 13, and contained in a chamber '54 in the upper casing section H is a rotary valve 15.

Contained in the lower casing section 12 is the usual equalizing discharge valve mechanism, comprising an equalizing piston 16 and a brake pipe discharge valve 11 to be operated by said piston. The equalizing piston has a chamber 5 18 at its upper face, which chamber is connected with the equalizing reservoir 2I through a passage and pipe 19, and a chamber 8I at its lower face, which chamber is in constant communication with the brake pipe II through a passage and pipe 82.

Associated with the brake valve device is a cut-out valve mechanism 9, comprising a valve 83 and a piston 84 adapted to operate said valve, seating of said valve being opposed by the pre*- sure of a spring 85 on said piston. The valve 83 is contained in a chamber 86. The piston has at one side a chamber 81 and at the opposite side a chamber 88, chambers 86 and 88 being separated by a partition wall 89 having an opening 9i through which a stem 8, connecting the valve 83 with the piston 84, is adapted to operate.

Also associated with the brake valve device is a brake application mechanism 1, comprising a piston 92 contained in a chamber 93 and a slide valve 94 contained in a valve chamber 95 and adapted to be operated by said piston, downward movement of said piston being opposed by the pressure of a spring 98 which normally retains the slide valve 94 in release position, as shown in Fig. 2. Associated with the brake application valve device is a reduction limiting reservoir 91, that is normally connected to the atmosphere through pipe and passage 98 having a restricted passage 99, cavity 80 in the slide valve 94 and atmospheric passage 10.

The combined electro-magnet signal and brake controlling valve device I9 for the locomotive includes a magnet valve device 6, comprising a magnet adapted to control oppositely seating 40 valves IOI and I02 contained in chambers I03 and 09 respectively, the chamber I04 communicating with the brake pipe I I through a passage and pipe 205 and pipe 82. Also contained in the chamber I04 is a spring I06, the pressure of i5 which tends to seat valve I02 and unseat valve HJI. Intermediate the valves IOI and I02 there is a chamber I01 that is open to an operating reservoir I08 through a passage and pipe I09.

The brake controlling valve mechanism I9 also includes a timing valve device 5, comprising a piston III having at one side a chamber II2 which communicates with the chamber I03 of the magnet valve device through a passage II3 that is open to a passage II4 having a restricted passage H5 and which leads to the chamber I03. The piston III has at its upper face a chamber H6 and is normally held in its lower position, as shown in Fig. 2, by the pressure of a spring I20, in which position its valve seat H8 engages the seat rib H9 and closes the passage II3.

Communication from chamber IIB to the atmosphere is established through passage H1 and leakage of fluid under pressure to the atmosphere from the chamber II2 past the piston Iii, when the latter is in its upper position, is prevented by engagement of the seat rib IIO on the piston III with the sealing seat 20.

A valve I2l, contained within a chamber I22 and having a fluted stem I23 extending into the chamber IH through a passage I24, is pressed into seated position by a spring I25 and is adapted to be unseated by the piston II I when the latter is moved to its upper position. The

chamber I22 is open to the chamber 93 of the brake application mechanism I through passage and pipe 99.

The chamber I03 is open to a timing reservoir I26 through the passage and pipe H4 and interposed in said passage is a chamber I27 containing a manually operable suppression valve I28 having a fluted stem E29 extending through a passage leading to the atmosphere. The stem is provided with a manually operable button for moving the valve from its seat for venting fluid under pressure from the chamber iii, the timing reservoir I26 and passage M3 to the atmosphere. The valve is normally held seated by the pressure of a spring 432.

An audible signal device such as a fluid pressure excited whistle I33 is connected to the passage 554 through a passage 53:3.

In charging, fluid under pressure flows from the main reservoir 22 through the feed valve 24, pipe and passage Edi, passages I42 and M3, chamber of the cut-out valve mechanism 9, opening ti, chamber 88, passage M4, passage and pipe to the brake pipe H. Fluid also flows "cm the main reservoir through pipe and passage to the chamber M containing the rotary brake valve stem "i5, and from passage 54% through passage Hit to the valve chamber 95 of the brake application mechanism and from thence through passage I5I in the piston 92, chamber chamber l22 of the timing valve device 5.

Fluid under pressure also flows from the feed valve 2 5 through pipe and passage iii, cavity M6 in the brake application slide valve 94, passage I 47, and passage I9 to the equalizing discharge valve piston chamber 18, and to the equalizing reservoir 2I. Fluid under pressure also flows from passage MI through passage I42, cavity M8 in the brake application slide valve 94 and passage i-"lii to the chamber 81 of the cut-off valve device 9.

Fluid under pressure flows from the brake pipe I! and pipe and passage 82 to chamber 8| of the equalizing discharge valve mechanism and through pipe and passage I 95 to chamber I a: of the magnet valve device 6, and from thence past the open valve I592, through passage Hit to intermediate chamber I07! and thence through pipe and passage N19 to the operating reservoir I08.

Assuming the enginemans brake valve device to be in running position and the electro-magnet valve of the combined electro-magnet signal and brake controlling valve device I9 is energized and the parts of said valve device are in release position, and that the circuit through the winding of the magnet valve device has just been interrupted for more than two seconds, the consequent deenergization of the electro-magnet of the magnet valve device 48 permits the spring to seat valve E82 and unseat valve liil. Unseating of valve It! permits fluid under pressure to flow from the operating reservoir Q68 past the unseated valve ill! to passage H4 and to the whistle 533 through passage I34, thus sounding an alarm.

Fluid under pressure also flows through pasiis and restricted passage I I5 to the timing reservoir I26, when the pressure of the fluid acting on the inner seated area of valve seat 5 it of the piston I! i builds up sufficiently to overcome the pressure of the spring Ill, said piston is moved upwardly and engages the stem I24 of the valve I2I, lifting it from its seat, thus and passage and pipe 98 to the,

opening communication from the chamber 93 of the brake application valve device to the atmosphere through passage and pipe 90, chamber I22, past the valve I 2I, passage I23, chamber H6, and atmospheric passage Ill. The seat rib Hi} on the upper face of the piston engages the sealing seat and prevents the how of fluid past the piston from the chamber H2.

Since the chamber 93 is open to atmosphere, the greater fluid pressure within the valve chamber 95 acting on the piston 52 forces it and the valve 94 to their application position, wherein cavity '86 in the slide valve 9; connects passage ids with atmospheric passage Til, thus reducing the fluid pressure in the chamber 81 of the cutoff valve device 9. The higher fluid pressure in the chamber 88 acting on the inner face of the piston 8d, forces it to its left position against the pressure of the spring 85, so that the valve 83 is seated and closes passage 9i and prevents the flow of fluid under pressure from the feed valve to the brake pipe Ii.

With the slide valve 94 in lower or application position, communication is established from the equalizing piston chamber 18 to the reduction limiting reservoir Bl through passage l5 cavity I 36 in the slide valve 94 and pipe and passage 38 containing the restricted passage 99, and fluid flows into said reservoir and reduces the fluid pressure within the chamber 18.

The higher brake pipe pressure within the chamber 81 acting on the equalizing piston it, forces said piston upwardly, thus lifting the discharge valve TI and opening the brake pipe to the atmosphere. Since a limited quantity of fluid under pressure news from the equalizing reservoir 2! to the reduction limiting reservoir 9?, the fluid pressure within the chamber 18 is reduced slightly, and when the brake pipe pressure falls slightly below that in chamber 78, the piston IE is moved downwardly, thus seating the discharge Valve TI and preventing further reduction in brake pipe pressure. In this manner, a reduction in brake pipe pressure at a service rate is made and a service application of the brakes is initiated at the locomotive by reason of the prolonged interruption of a circuit through the magnet valve device 40.

However, should the circuit through the magnet valve device be interrupted momentarily by opening of a signal switch for a period of time less than two seconds, the magnet valve I92 will be seated and the valve IGI unseated for a corresponding length of time, thus momentarily sounding the whistle by permitting a blast of fluid under pressure to flow from the operating reservoir I08 to the passage H4, past the valve hill in the manner previously described. Since it requires two seconds or more for the fluid under pressure supplied to the passage Hi to enter the timing reservoir and build up sufficient fluid pressure therein to lift the piston I l I, said piston will not respond to the fluid under pressure within passage H4 and no brake application will be initiated.

Should it be desirable, upon a failure of a conductor of the electro-rnagnet brake equipment, or failure of the current supply, to suppress the automatic application of the brakes as above described, the engineman may upon hearing the warning signal, immediately press the suppression valve and open the valve I28, thereby preventing the pressure ofthe fluid in the passage H4 from building up suili ciently to lift the piston I II.

The engineman may hold the suppression valve I28 open until the pressure of the fluid in the operating reservoir I08 is below that necessary to lift the piston III and thus suppress an automatic application of the brakes until after the operating reservoir has been recharged as a result of reenergization of the magnet valve device 40.

In such an event, the engineman may operate the brake valve device so as to control the brakes pneumatically in the usual manner of pneumatic control, and bring the train to rest at any desired point in order to make repairs to the electrical control system.

Provision is made for also simultaneously initiating an automatic application of the brakes at the rear end of the train by causing a reduction in brake pipe pressure at a service rate by discharging fluid from the brake pipe at a valve device carried upon the caboose. For this purpose the combined electro-magnet signal and brake controlling valve device 38 is provided on the caboose, which device is illustrated in Fig. 3 and comprises the magnet valve device 60 similar to the magnet valve device 40 on the locomotive, an operating reservoir I5I, a timing valve device I52, a timing reservoir I53, a brake application valve device I54, an equalizing reservoir I55, a reduction limiting reservoir I56, and a discharge valve device I51.

The magnet valve device 60 comprises an electro-magnet adapted to control opposite seating valves I58 and I59 and contained in chambers IEI and I62 respectively, the chamber I62 communicating with the brake pipe II through passage and pipe I63. Also contained in the chamber I62 is a spring I64, the pressure of which tends to seat valve I59 and unseat valve I58. Intermediate the valves I58 and I59 is a chamber I60 that is open to the operating reservoir I5! through a passage and pipe I64.

The timing valve device I52 contains a piston I65 having at one side a chamber I66 from which communication is established, when the piston is in raised position, to the chamber I6I through passage I14 and passage I61, having a restricted passage I68. The piston has at its upper face a chamber I69, and is normally held in its lower position by the pressure of a spring I1I, in which position its valve seat I12 engages the seat rib I13 and closes the passage I14.

The chamber I69 is open to the atmosphere through passage I15 and leakage of fluid under pressure to the atmosphere from the chamber I66 past the piston I65, when the piston is in its upper position, is prevented by engagement of the seat rib I16 on the piston with the sealing seat I11.

A valve I18 contained within a chamber I and having a fluted stem I19 extending into the chamber I69 through a passage I8I, is pressed in seated position by a spring I82 and is adapted to be unseated by the piston I65 when the latter is moved to its upper position.

The brake application valve device I54 comprises a piston I83 having on one side a piston chamber I84 and on the other side a valve chamber I85 containing a slide valve I86 adapted to be operated by a piston stem I81 carried by the piston I83.

The piston chamber I84 is open to the chamber I80 of the timing valve device I52 and contains a spring I88, which normally presses the piston in release position against a sealing seat rib I89. Communication is established from the piston chamber I84 tothe valve chamber I35 by a passage I9I in the piston I83.

The equalizing discharge valve mechanism I51 comprises a piston I92 and a brake pipe discharge valve I93 adapted to be operated by said 5 piston. The equalizing piston has a chamber I94 at its upper face, which chamber is open to the equalizing reservoir I55 through a passage and pipe I95 having a restricted passage I96, and a chamber I91 at its lower face, which chamber is in constant communication with the brake pipe II through a passage and pipe I63.

The combined electro-magnet signal and brake controlling valve device 38 is charged from 'the brake pipe II in the following manner. Fluid under pressure flows from the brake pipe II through passage and pipe I63, chamber I62 of the magnet valve device 69, past the open valve I59, the passage I98, chamber I68 and passage and pipe I64 to the operating reservoir I5 I. Fluid 20 under pressure also flows from the passage I63 to the valve chamber I85 of the brake application valve device I54 and from thence through port I9I in the piston I83 to the piston chamber I84. The fluid pressure acting on the upper 25 face of the piston and the pressure of the spring 188 tend to hold the piston in release position upon the sealing seat rib I89.

With the piston I83 and slide valve I86 in release position, as shown in Fig. 3, fluid under 30 pressure also flows from passage I63 through cavity 262 in the slide valve, passage I95 to the equalizing piston chamber I94 and to the equalizing reservoir I55 through the restricted passage I96 in passage I95. Fluid under pressure 35 further flows from passage I63 to the chamber I91 at the under face of the equalizing piston I92.

Upon deenergization of the electro-magnet device 60 for more than two seconds, as a result of an accidental break in the electrical break control 40 system, or failure of the current supply, the valve I59 of the magnet valve device is seated and the valve I58 is unseated. Unseating of the valve I58 permits fluid under pressure to flow from the operating reservoir iEI through 45 pipe and passage I64, chamber I69, passage 208, past the open valve I58, chamber I6I, and passage I61 to the whistle 209 which is thus sounded. Fluid under pressure is also supplied through passage I61, restricted passage I68, passage I14 and passage and pipe 294 to the timing reservoir I53, until pressure of the fluid therein and in the passages 204 and I14 and acting on the inner seated area of the seat I12 of the piston I65 builds up sufiiciently to lift said 5 piston against the pressure of spring I'H, so that it unseats the valve I18. When the valve I18 is unseated, fluid under pressure flows from the chamber I84 of the brake application valve device I54 to the atmosphere through passage chamber I80 of the timing valve device I52, past the open valve I18, passage I8I, chamber I69 and atmospheric passage I15.

The greater fluid pressure acting on the lower face of the piston I83 moves it to its upper or application position against the pressure of the spring E88, moving the slide valve I86 to application position.

With the slide valve I86 in application position, passage I63 leading from the brake pipe II to the equalizing piston chamber I94 is blanked and communication is established from the chamber I94 to the reduction limiting reservoir I56 through passage I95, cavity 282 in the slide 75 valve I86, and passage and pipe 206 having a restricted passage 201.

The greater fluid pressure acting on the under side of the equalizing piston I92 forces the piston upwardly and opens the discharge valve I93, thus permitting fluid under pressure to flow from the brake pipe II to the atmosphere from the chamber I91 past the valve I93 and through atmospheric passage 208 at a service rate, thus initiating a service application of the brakes at the rear end of the train. When the brake pipe pressure falls slightly below that of the equalizing piston chamber !94, determined by the flow of fluid from the equalizing reservoir I to the reduction limiting reservoir I55, the piston is moved downwardly and closes the discharge valve I93.

From the foregoing it is apparent that when the circuit through the electro-magnet on the caboose is interrupted for a sufiicient time to permit the pressure of the fluid in the timing reservoir I53 and acting on the timing piston m5,

to build up sufficiently to overcome the pressure of the spring III, the piston IE5 is raised and a service application of the brakes is initiated.

The associated parts of the mechanism are so proportioned that at least two seconds are required after deenergization of the electro-magnet valve device 60 in order to build up suflicient fluid pressure to raise the piston I for initiating an application of the brakes. Consequently, for the reasons given relative to the brake controlling valve device carried on the locomotive and shown in Fig. 2, an appli ation of the brakes will not be initiated by the valve device carried on the caboose when the electromagnet 60 is deenergized for a period of time less than two seconds, as when interrupted by the signal ,switches H, 36 and 42, which are incapable of retaining the circuit open for two seconds or more. In the event of a circuit interruption due to the opening of a signal switch or damage to a conductor of the electric brake controlling system, the whistle 209 that is open to the passage I61 will sound.

A suppression valve device 2II contained in a chamber 2!!) open to passage 204, comprises a valve 252 normally held' closed by a spring 2I3, and having an operating stem extending through an atmospheric passage 2M. The suppression valve 2 is adapted to be manually operated by a trainman on the caboose, for the purpose of suppressing initiation of a brake application should suppression be desired. The valve releases fluid from the passage 2M and prevents when unseated, a sufiicient build-up of fluid pressure in the timing reservoir and passage IM to lift the piston I65.

By reason of the provision of the brake controlling valve devices I9 and 38 on the locomotive and caboose respectively, the brakes may be automatically applied simultaneously at the front and rear of the train in the event of failure, for more than a predetermined time, of the electric control system or the initiation of the application of the brakes may be suppressed at either or both ends of the train should the trainman so desire.

Signalling from the ends or from intermediate points on the train may be accomplished without interfering with the protective characteristics of the electrical control system, and without danger of initiating an application of the brakes.

In Figs. 4 and 5, modified combined. electromagnet signal and brake controlling valve devices are illustrated, wherein the devices are capable of automatically initiating, upon failure of the electrical control equipment, an emergency application of the brakes on the front and rear ends of a train.

The equipment shown in Fig. 4 is for use on the locomotive and is similar to that disclosed in Fig. 2, with the exception that the enginemans brake valve device is provided with a brake pipe vent valve device 4 that is controlled by the brake application valve device I for opening the brake pipe to atmosphere for reducing the brake pipe pressure at an emergency rate after the magnet valve device 45 is deenergized for a predetermined period of time.

Furthermore, the communication between the feed valve device 24 and the equalizing chamber 8 and equalizing reservoir 2! is not controlled by the slide valve 94 of the brake application valve device, as in the case of the equipment shown in Fig. 2, and a valve oper ating reservoir 2E5 for operating the brake pipe vent valve, is substituted for the reduction limiting reservoir 9'! of the device shown in Fig. 2.

Referring to Fig. 4, the brake pipe vent valve device 4 comprises a piston 2H5 having at one face thereof a piston chamber 2H and at the other face a chamber 2I8 communicating with a chamber 226 through a passage 222 that is adapted to be closed by a valve 2E9 in valve chamber 22%, and which is carried by a fluted stem 2t" that extends through the passage in the partition wall 223 between the chambers 2I8 and 226. The chamber 226 is open to the brake pipe iI through passage and pipe 82 and the valve 2 I 9 is normally held seated by a spring 224.

The operation of the cut-out valve device 5% for controlling communication from the feed valve 24 to the brake pipe is controlled a cavity I 58 in the slide valve 94 inthe manner of equipment shown in Fig. 2, the said cut-out valve serving to close said communication when an application of the brake is automatically initiated.

The equipment shown in Fig. 4 is charged in the manner of equipment shown in Fig. 2, with the exception that the operating reservoir 255 is charged from the main reservoir 22 through pipe and passage M5, passage I40, valve chamber es, port 225 in the slide valve 84 and passage I and pipe 226.

In the event of a failure of the current supply, or the control conductors on the electrical brake controlling equipment, for a predetermined time, the consequent deenergization of the magnet valve device 49 causes the fluid pressure in the piston chamber 93 to be reduced to atmospheric pressure in the manner of the equipment shown in Fig. 2. The higher main reservoir pressure within the valve chamber 95 acting on the upper side of the piston 92, forces the piston to its lower brake application position against the pressure of the spring 55, carrying the slide valve 94 to application position.

With the slide valve in application position, communication is closed from the feed valve device 24 to the brake pipe in the manner of the equipment shown in Fig. 2,, and communication is established from the operating reservoir 2H: to the piston chamber 2!! of the brake pipe vent valve device 4 through pipe and passage 226, cavity 221 and passage 22%. The chamber 21-8 is constantly open to the atmosphere throughpassage 222 and atmospheric passage 269 and the greater pressure in the chamber 2II moves the piston to the right and opens the valve 2I9 against the pressure of the spring 224 and the brake pipe pressure acting on the valve 2.!9, thus opening communication from the brake pipe II through pipe and passage 82, chamber 22!], past the open valve 2I9, passage 222 and atmospheric passage 259. The rake pipe pressure is thus reduced at an emergency rate and initiates an emergency application of the brakes at the front end of the train.

A restricted port 239 is provided in the piston 2E6 for relieving the pressure in the chamber ZIT, to permit the return of the piston 2I6 to release position shown when the slide valve 94 is returned to its upper release position.

The equipment just described, like that shown in Fig. 2, will not initiate an application of the brake when the circuit to the electro-magnet valve device 40 is deenergized for a period of time less than that required to operate the timing valve device, as when a signal switch 36 is opened for the purpose of signalling.

Referring to Fig. 5, a modified form of combined electro-magnet signal and brake controlling valve device is disclosed and is adapted for use on the caboose for sounding a warning signal or initiating an emergency application of the brakes at the rear end of the train simultaneously with the initiation of the emergency application of the brakes at the front end of the train.

The modified equipment comprises the magnet valve device 60 which is similar to that shown in Fig. 3, an operating reservoir II, a timing reservoir I55 and a brake pipe vent valve device 23I. The brake pipe vent valve device comprises a piston 232 having at the upper face a chamber 233 open to the chamber I6I of the magnet valve device 60 through a passage 234 and a restricted passage 235, and at the lower face a chamber 236 constantly open to the atmosphere through atmospheric passage 231.

The piston is provided with a stem 238 which carries a valve 239 contained within a valve chamber 24I that is open to the brake pipe II. The valve is normally held in closed position upon a seat rib 242 surounding a passage 243 in the partition wall separating the chambers 236 and MI, by a spring 244.

A suppression valve device similar to that shown in Fig. 3 is associated with the timing reservoir E55 and comprises a valve 2I2, within the reservoir I56, having a fluted stem 250 extending through an atmospheric passage 2M and which may be manually operated for the same purpose as the suppression valve devices shown in Figs. 2 and 3. The valve 2I2 is normally held seated by a spring H3. The timing reservoir is open to the passage 234 through a passage 245.

With the parts of the brake control valve device in the release position shown in Fig. 5, the equipment is charged from the brake pipe I I, fluid under pressure flowing therefrom to the operating reservoir I5I through pipe and passage I63, chamber I62 of the magnet valve de-. vice 65, past the open valve I59, passage I98, intermediate chamber I55, and passage and pipe I64.

When the electro-magnet valve device 60 is deenergized, valve I59 is seated and valve I56 is unseated. With valve I58 unseated, fluid under pressure flows from the operating reservoir I5! through pipe and passage I64, chamber I60, passage 293, chamber I6I, passage 234 to the timing valve reservoir I56, through passage 245, to the piston chamber 233 and to the warn- 5 ing whistle 209.

When the pressure of the fluid in the passage 234 and in the timing reservoir I56 and acting on the piston 232 in the piston chamber 233, builds up sufiiciently to overcome the brake 10 pipe pressure and the pressure of the spring 24% acting on the valve 239, the piston is moved downwardly so as to open the valve 239. With the valve 239 open, fluid under pressure is discharged from the brake pipe II to the atmosphere at an emergency rate through passage 243, chamber 236 and atmospheric passage 23?, thereby initiating an emergency application of the brakes.

As with the previously described brake controlling valve devices, the time required for building up sufficient fluid pressure to operate the piston 232 is greater than the time during which the circuit through the magnet valve device 60 can be maintained open during a 25 signalling operation, and consequently an emergency application of the brakes cannot be automatically initiated by the control valve device just described during a signalling operation.

It is apparent from the foregoing that the equipment provided on the locomotive and caboose of the train is adapted to simultaneously sound a warning at the locomotive and caboose when an interruption of the circuit for the electrical brake controlling system occurs and will automatically initiate an application of the brakes at a service or emergency rate, depending on which equipment is used, should the inter ruption of the circuit or the loss of current supply endure for more than a predetermined time, for example, two seconds. Means are provided for suppressing initiation of the brake application if desired and the safety system may be used for signalling purposes without causing initiation of a brake application.

While but two embodiments of the invention are disclosed, it is obvious that additions and omissions and other changes may be made in the construction and arrangement of the equipment without departing from the spirit of the invention.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an electric brake system, the combination with means operating on a normally open circuit for controlling the brakes, of means operating on a normally closed circuit and subject to the impedance characteristics of said normally open circuit for also controlling the brakes.

2. In an electrical brake system, the combination with means operating on a normally open circuit and adapted to initiate an application oi the brakes when the said means is energized, of a second means including a signal device and a brake controlling device and operating on. a normally closed second circuit including a portion of the first said circuit, adapted to initiate an application of the brakes and operate to give a signal when said second means is deenergized for a predetermined time and to operate only to give a signal when said second means is deenergized for a period of time less than said predetermined time.

3. In an electrical brake system, the combinationwith means operating ona normally open vent said brake controlling device from initiatcircuit and adapted to initiate an application of the brakes when the said means is energized, of a second means including a signal device and a brake controlling device and operating on a normally closed second circuit including .a portion of the first said circuit, adapted to initiate an application of the brakes and operate to give a signal when said second means is deenergized for a predetermined time and to operate only to give a signal when said second means is deenergized for a period of time less than said predetermined time, and a manually operable means for interrupting said second circuit and adapted to automatically close said circuit within a period of time after interruption less than said predetermined time.

4. In an electrical brake system, the combination with means operating on a normally open circuit and adapted to initiate an application of the brakes when the said means is energized, of a second means including a signal device and a brake controlling device and operating on a normally closed second circuit including a portion of the first said circuit adapted to initiate an application of the brakes and operate to give a signal when said second means is deenergized for a predetermined time and to operate only to give a signal when said second means is deenergized for a period of time less than said predetermined time, a third means so connected in said second circuit that it is operative when the said included portion of said first circuit is interrupted to open said second circuit and hold it open indefinitely, a fourth means for preventing the interruption of the second circuit by said third means for a second predetermined time after the circuit through said third means has been interrupted, and a manually operable means for interrupting said circuit through said third means adapted to automatically close said circuit within a period of time after interruption less than the first and second said predetermined times.

5. In an electric brake system, the combination with means operating on a normally open circuit for controlling the brakes, of a normally closed circuit, a source of current in said normally closed circuit, means in said normally closed circuit operable automatically upon damage to either of said circuits for opening the circuit through said source of current, and means operable upon the opening of said normally closed circuit for initiating an application of the brakes.

6. In an electric brake system, the combination with means operating on a normally open circuit for controlling the brakes, or" a normallyclosed circuit, a source of current in said normally closed circuit, switch means included in said normally closed circuit operableautomatically upon damage to either of said circuits for opening the circuit through said source of current, means including a signal device and a brakev controlling device operable upon opening of said normally closed circuit for warning of said damage and for initiating an application of the brakes, a signal switch device operable to open and close said normally closed circuit to control the operation of the warning means to operate said signal device, means operable to prevent said switch means from operating to circuit-opening position when said signal switch device is operated to open and close the normally closed circuit, and means operable to preing an application of the brakes when said signal switch device is operated to open and close the normally closed circuit.

'7. .In an electric brake system, the combination with means operating on a normally open circuit for controlling the brakes, of a normally closed circuit, a source of current in said normally closed circuit, switch means included in said normally closed circuit operable automatically upon damage to either of said circuits for opening the circuit through said source of cura brake controlling means operable upon opening of said normally closed circuit through said switch means for initiating an application of the brakes, a signal operable upon opening of said normally closed circuit for warning of said damage, a signal switch device operable to open and close said normally closed circuit to control the operation of said signal for the purpose of signalling, and means operable to prevent said switch means from operating to circuit-opening position when said signal switch device is operated to open and close the normally closed circuit.

8. The combination with electrically controlled devices on the cars and caboose of a train adapted upon energization to effect an application of the brakes, and three main train conductors connected to said devices, of a source of direct current on the head end of the train normally cut out of circuit with said train conductors, a switch device operable to close the circuit through the train conductors, source of current and devices to eifect the energization of said devices, a normally closed circuit including said main train conductors, a source of alternating current for said normally closed circuit, means included in said normally closed circuit and responsive to variations in current in said normally closed circuit for effecting an application of the brakes.

9. The combination with electrically controlled devices on the cars and caboose of a train adapted upon energization to effect an application of the brakes, and three main train conductors connected to said devices, of a source of direct current on the head end of the train normally out out of circuit with said train conductors, a switch device operable to close. the circuit through the train conductors, source of current and devices to effect the energization of said devices, a normally closed circuit including said main train conductors, a source of alternating current for said normally closed circuit, separate means at the head end and rear end of the train and responsive to variations in current in said normally closed circuit for initiating an application of the brakes at the head and rear ends of the train.

10. The combination with electrically controlled devices on the cars and caboose of a train adapted upon energization to effect an application of the brakes, and three main train conductors connected to said devices, of a source of direct current on the head end of the train normally out out of circuit with said train conductors, a switch device operable to close the circuit through the train conductors, source of current anddevices to effect the energization of said devices, a normally closed circuit including said main train conductors, a source of alternating current for said normally closed circuit, separate current responsive means at the head end and rear end of the train and included in said normally closed circuit adapted upon deenergization of said normally closed circuit to initiate an application oi the brakes at the head and rear end of the train.

11. In electric bralze system, the combination with means operating on a normally open circuit for controlling the brakes, of a normally closed circuit system for indicating the condition of said normally open circuit and including a current transmission and two warning circuits inductively energized by current in said trans mission circuit, and means responsive to variations in current in any of said circuits for effect ing an application of the brakes.

12. In an electric brake system for a train of vehicles, the combination with an electric brake controlling circuit system including two electric circuits, each extending from vehicle to vehicle, means located one vehicle to supply current to one of said circuits, means located in another vehicle to be energized by current flow in the first mentioned circuit and to thereby produce a current flow in the other circuit, and means lo cated on one of said vehicies and responsive to variations current in said other circuit for initiating an application of the brakes.

In an electric brake system for a train of vehicles, the combination With an electric brake controlling circuit system including two electric circuits, each extending from vehicle to vehicle, means 19L ted in one vehicle to supply current to one of ca. circuits, means located in another vehicle to be energized by current flow in the first mentioned circuit and to thereby produce a current flow in the other circuit, and means located on two of said vehicles and responsive to variations in cur-i in said other circuit for initiat ing an application oi the brakes at the head and rear end of the train.

14. In a fluid pressure brake system, the combination with a valve device operative upon variations of fluid pressure to effect operation of the brakes, an electric current responsive device operative upon a variation in current for efiecting a variation in fluid pressure acting on said device and means for delaying for a predeterr ed time the operation of said current responsive device to effect a variation in fluid pressure acting on said valve device after the current acting on said current responsive device has varied.

15. In a fluid pressure brake system, the combination W a valve device operative upon variations of fluid pressure to effect operation of the brakes, of an elec. is current responsive device operative upon a variation in current for effecta va' ation in fluid pressure acting on said valve dew for delaying for a predetermined time the operation of said current responsive device to effect a va iation in fluid pressure after the current acting on said current responsive evic has varied, manually operablemeans for ef g a variation of said current and means automatically limiting the duration of said current variation to a period of time less than said predetermined time.

16. In a fluid pressure brake system, the combination Wi h a brake valve device having a brake pipe discharge valve and a device operating on variati as of fluid pressure for controlling discharge valve, of a current responsive valve device operating upon a variation of ourront for a predetermined t ne for effecting variations in the fluid acting on said device, and means for rendering said current responsive valve device ineffective for varying the fluid pressure acting on said device.

17. In a fluid pressure system, the combination with a valve device having a brake pipe discharge valve and a device operating on varia tions in fluid pressure for controlling said dis charge valve, an operating reservoir, a valve means for effecting variations in the pressure of the fluid acting on said device and operating on fluid from said reservoir, and a current responsive valve device for controlling the supply of fluid under pressure from said reservoir to said valve means.

18. In a fluid pressure brake system, the combination wit i a valve device having a brake pipe discharge valve and a device operating on variations in fluid pressure for controlling said discharge valve, of an operating reservoir, a valve means for elfecting variations in the pressure of the fluid acting on said device and operating on fluid from said reservoir, a ctrent responsive valve device for controlling the supply of fluid under pressure from said reservoir to said valve means, and a uming means cooperating with said valve means for controlling the rate of pressure build-up of the fluid under pressure supplied from said operating reservoir and acting on said valve means.

19. In a fluid pressure brake system, the combination With a valve device having a brake pipe discharge valve and adevice operating on variations in fluid pressure for controlling said di charge valve, of an operating reservoir, a valve means for eife ng variations in the pressure of the fluid acting on said device and operating on fluid from said reservoir, a current responsive valve device for controlling the supply of fluid under pressure from said reservoir to said valve means, a timing means cooperating with said valve means for determining the rate of pressure build-up or" the fluid under pressure supplied from said operating reservoir and acting on said valve means, and means for rendering said timing means ineffective to determine the rate of pressure build-up of the fluid under pressure acting on said valve means.

20. In a fluid pressure brake system, the combination with a valve device having a brake pipe discharge valve and a device operating on vaiations in fluid pressure for controlling said discharge valve, cf an operating reservoir, a valve means for effecting variations in the pressure of the fluid acting on said device and operating on fluid from said reservoir, a current responsive valve device for controlling the supply of fluid under pressure from said res voir to said valve means, and a timing reservoir communicating with said valve means for controlling the rate of pressure build-up of the fluid under pressure supplied from said operating reservoir and acting on said valve means.

In a fluid pressure brake system, the combination with a valve device having a brake pipe discharge valve and a device operating on variations in fluid pressure for controlling said dis- 6 bination with a valve device having a brake pipe discharge valve and a device operating on variations in fluid pressure acting thereon for controlling said discharge valve, of an operating reservoir, a valve means operating on fluid supplied from said reservoir for efiecting a varia tion in the pressure of the fluid acting on said device when the pressure on said valve means exceeds a predetermined value, a current responsive-valve device for controlling the supply of fluid under pressure supplied from said operating reservoir and acting on said valve means, and means for controlling the rate of pressure buildup of the fluid supplied from said reservoir and acting on said valve means.

23. In a fluid pressure brake system, the combination with a valve device having a brake pipe discharge valve and a device operating on an increase in fluid pressure acting thereon for effecting opening movement of said discharge valve, of an operating reservoir, a valve means operating on fluid under pressure supplied from said reservoir for effecting an increase of fluid under pressure acting on said device when the pressure on said valve means exceeds a predetermined value, a current responsive valve device for controlling the supply of fluid under pressure. supplied from said operating reservoir and acting on said valve means, and a timing reservoir for receiving fluid under pressure from said operating reservoir for determining the rate of pressure build-up of the fluid under pressure acting on said valve means.

24. In a fluid pressure brake system, the combination with a valve device having a brake pipe discharge Valve and a device operating on an increase in fluid pressure acting thereon for effecting opening movement of said discharge valve, of an operating reservoir, a valve means operating on fluid under pressure supplied from said reservoir for effecting an increase of fluid under pressure acting on said device when the pressure on said valve means exceeds a predetermined value, a current responsive valve device for controlling the supply of fluid under pressure supplied from said operating reservoir and acting on said valve means, a timing reservoir for receiving fluid under pressure from said operating reservoir for determining the rate of pressure build-up of the fluid under pressure acting on said valve means, and a manually operable valve device for preventing the pressure of the fluid supplied from said operating reservoir and acting on said valve means from exceeding said predetermined value.

25. In a fluid pressure brake system, the combination of a brake valve device comprising manually operable means and a brake pipe discharge valve controlled by said manually operable means and operative upon variations in fluid pressure for venting fluid from the brake pipe, a device operating on variations of fluid pressure for also controlling the operation of said discharge valve, and a current responsive valve device for effecting variations in the fluid pressure acting on said device.

26. In a fluid pressure brake system, the combination of a brake valve device comprising manually operable means and a brake pipe discharge valve controlled by said manually operable means and operative upon variations in fluid pressure for venting fluid from the brake pipe, a device operating on variations of fluid pressure for also controlling the operation of said discharge valve, a current responsive valve device operative upon a variation of current to effect variations in the fluid pressure acting on said device, andtiming means operative .to prevent said current responsive meansfrombeing operative .to efiect variations in the fluid pressure acting on said device unless said current variation endures longer than a predetermined time.

27. In an electric brake system, the combination ofmeans operating on a normally open circuit for controlling the operation of the brakes, and means operating ona normally energized circuit maintained closed through a portion of said normally open circuit, said second means being effective to cause an application of the brakes only after the said normally energized circuit has been deenergized longer than a predetermined time.

28. In an electric brake system, the combination of means operating on a normally open circuit for controlling the operation of the brakes, means operating on a normally energized circuit maintained closed through a portion of said normally open circuit, said second means being effective upon the deenergization of said normally energized circuit to cause an application of the brakes, and timing means for preventing said second means from being eifective to cause an application of the brakes unless deenergization of said normally energized circuit continues for a period longer than a predetermined time.

29. In an electric brake system, the combination of means operating on a normally open circuit for controlling the operation of the brakes, and means operating on a circuit normally maintained closed through a portion of said normally open circuit for causing an audible indication and an application of the brakes to be eifected upon the integrity of said circuits being destroyed.

30. In an electric brake system, the combination of means operating on a normally open circuit for controlling the operation of the brakes, means operating on a circuit normally maintained closed through a portion of said normally open circuit for effecting an application of the brakes upon the integrity of said circuits being destroyed, and signal means controlled by said second means and effective to give indication as to the lack of integrity of said circuits.

31. In an electric brake system, the combination of means operating on a normally open circuit for controlling the operation of the brakes, means operating on a circuit normally maintained closed through a portion of said normally open circuit for effecting an application of the brakes upon the integrity of said circuits being destroyed, signal means controlled by said second means and effective to give indication as to the integrity of said circuits, and manually operable means included in said normally closed circuit and operative to cause said signal means to give an audible signal without causing an application of the brakes.

32. In an electric brake system, in combination, a normally open circuit, means operating on said normally open circuit for controlling the brakes, a second circuit inductively coupled to said normally open circuit and adapted to be normally maintained closed through a portion of said normally open circuit, and means operating on said second circuit for also controlling the brakes.

33. In an electric brake system, in combination, electro-responsive means operative to control the brakes, a normally open circuit whereby operation of said electro-responsive means is effected, another electro-responsive means also operative to control the brakes, and a second circuit inductively coupled to said normally open circuit and adapted to be normally maintained closed through a portion of said normally open circuit whereby operation of said second electro-responsive means is effected.

34. In an electric brake system, in combination, a normally deenergized circuit, means 0perable upon energization of the said circuit for efiecting an application of the brakes, a nor= mally energized circuit including a portion of said first circuit, a second means operable on said normally energized circuit and adapted to effect an application of the brakes upon deenergization of said normally energized circuit, and means for preventing the operation of said sec ond means to effect an application of the brakes unless the deenergizationof said second circuit continues for more than a predetermined time. 10

RAYMOND E. MILLER. 

